FR2965123A1 - DEVICE AND METHOD FOR MANAGING THE ELECTRICAL POWER SUPPLY OF A LOAD - Google Patents

Abstract

The invention relates to a device for supplying electric current to a load (1), in particular an electric motor vehicle engine with a hybrid or electric motor, said device comprising a plurality of direct current sources (7), divided into modules ( 8) in which said current sources (7) are connected in series, said modules (8) being connected in parallel with the load. It also relates to a method for managing the electric power supply of a load (1), using such a device.

Description

Device and method for controlling the supply of electrical power to a car

The present invention relates to a device for supplying electric current to a load, particularly an electric motor vehicle engine with hybrid or electric motorization. It also relates to a method for managing the electric power supply of a load, using such a device. The invention aims in particular the power supply of an electric motor with a power ranging from about ten kilowatts to about one hundred kilowatts. This is, for example: - for the weakest powers, that is to say of the order of ten kilowatts, engines for assisting the propulsion of a vehicle automobile also equipped with a heat engine providing, for the most part, propulsion (motorization "mild hybrid" in English), - for intermediate powers and for the strongest powers, engines to ensure the propulsion a motor vehicle for longer periods but still alternating with a heat engine (engine "full hybrid" in English), or motor vehicle engines whose motorization is entirely electric. However, these indications do not exclude the use of the invention in a quadricycle or tricycle with fully electric motorization, even if it is, in such applications, motorizations using powers located in the bottom of the range mentioned above. Currently, it is known power devices comprising a battery accumulator, mounted in series, and a voltage converter to raise the voltage level provided by the batteries.

Sufficient voltage levels can thus be achieved while limiting the number of accumulators to be mounted in series, which improves the reliability of the battery. Indeed, in a series connection, it suffices that one of the elements is faulty so that the battery is faulty. A solution to overcome this drawback is to provide by-pass to bypass the faulty element or elements but it requires many additional components. However, a common disadvantage of series-mounted devices is that the available power is limited. In addition, even when using a voltage converter, the number of accumulators remains too large and the need for greater reliability remains. For this, one can imagine having the accumulators in parallel but it is necessary to provide elements that can deliver a high voltage. Although such a need may be reduced by the use of voltage converters, another difficulty in using parallel-connected accumulators is balancing between the accumulators. It is more precisely to ensure that the currents flowing in each accumulator in operation are similar so that the accumulators are solicited homogeneously. By multiplying the number of accumulators placed in parallel, such balancing is complex and costly. The invention proposes to overcome these difficulties and relates to a device for supplying electric current to a load, particularly an electric motor vehicle engine with hybrid or electric motorization. According to the invention, said device comprises a plurality of direct current sources, distributed in modules in which they are connected in series, said modules being connected in parallel with the load. This can both limit the number of elements mounted in series, which improves reliability, and limit the number of elements connected in parallel, which facilitates control of the device. One can also obtain an interesting compromise in terms of voltage and available power.

In particular, we can choose for the modules a voltage level below the threshold, namely today 60 V, requiring the presence of a galvanic isolation. It will be possible to choose a voltage level of about 48 V for each module.

Current sources consist, for example, of identical unitary elements. These include, in particular, accumulators having a voltage level of the order of a few volts. Each module has, for example, the same number of unit elements, including a dozen. In this way balancing is facilitated.

However, modules can also be different in nature. By this we mean basic voltage, capacity or, among other things, different technology. Furthermore, the device according to the invention may comprise current regulation means for controlling the level of current exchanged between the modules and / or the load, independently for each module. It is thus possible to limit the level of voltage supplied by the modules by using said means as a voltage booster. In this way, power is supplied to motors operating, for example, under several hundred volts. Said current regulation means may also be provided capable of soliciting said modules differently to supply the load, reload modules differently from the load or recharge one or more of said modules from one or more other said modules, in particular according to the nature and / or operating state of the modules, defined by a state of charge and / or health of the modules. By state of health, one hears, for example, an image of the internal resistance and / or the capacity of the module.

According to various embodiments: - the current regulation means comprise converters, each module being connected to one of said converters, provided capable of performing a voltage conversion between the associated module and the load, - converters are provided capable to make an increase in the voltage level delivered by the modules, - the converters are provided reversible, - the converters comprise a capacitive element connected in parallel with the load, - the converters are connected between two output terminals, common to all the modules, - the same capacitive element is shared between several or all of said converters, This last characteristic is a particularly simple solution for energy recovery from one module to another, through said capacitive element. The device according to the invention may further comprise means for identifying the nature of the modules and / or the means for measuring the operating state of the modules. It is, in particular, a load indicator of each of the modules.

The invention also relates to a method for managing the electric power supply of a load, in particular an electric motor vehicle engine with hybrid or electric motorization, in which a plurality of DC power sources are provided, divided into modules in which said current sources are connected in series, said modules being connected in parallel with the load, and a current regulation is carried out making it possible to control the level of current exchanged between the modules and the load, independently for each module. An advantage of an independent management modules is that it allows an improvement in the life of the assembly, including by modulating their use in case of partial performance needs. According to various embodiments: a module operating state, defined by the state of charge and / or the state of health of the modules, is monitored; these modules are solicited in a different way to power the load, depending on the operating state of each of the modules; - the modules are recharged differently from the load, depending on the operating state of each of the modules; - one or more of the modules are recharged; from one or more other of said modules, depending on the operating state of each of the modules, the absence or malfunction of one of said modules is detected, said module being faulty, said faulty module is isolated and adapted the current regulation performed at the other modules to ensure the supply of a voltage to the load taking into account the absence or malfunction of the faulty module, - we identify the nature of each said modules and adapts the current regulation performed for each module to the nature of said module. The invention will be better understood in the light of the following description which is given for information only and which is not intended to limit it, accompanied by the attached figure which illustrates an exemplary embodiment of a device. supply according to the invention. As illustrated, the invention thus relates to a device for supplying an electric current to a load 1. This comprises, for example, an electric machine 2 and an inverter / rectifier 3. The latter makes it possible to transform a direct current, between its input terminals 4, 5, an alternating current, in particular three-phase, at its output terminals 6a, 6b, 6c, connected to the motor, and vice versa. However, the load may of course be other components. It may, in particular, include several electrical machines, for example powered by the current delivered by the inverter / rectifier.

According to the invention, said device comprises a plurality of direct current sources 7, distributed in modules 8 in which they are connected in series, said modules 8 being connected in parallel with the load 1. It is thus possible to obtain levels of satisfactory voltage without using too many current sources connected in series. In the case of an application to a vehicle, the modules may be located in different locations of the vehicle. Current sources consist, for example, of identical unitary elements. This means that the current sources all have, for example, the same capacity and the same voltage level. It may even be all structurally similar elements. Said unitary elements are, for example, batteries, in particular batteries of the lithium-ion type. They have voltage levels of the order of a few volts, for example of the order of 3 to 4 V.

Each module 8 may include the same number of unit elements. The device thus has the same capacity and the same voltage level at the terminals of each module 8. Each module comprises, for example, of the order of ten to fifteen individual elements. With the voltage levels of the unit elements mentioned above, consequently, significant voltage levels are reached at the terminals of the modules 8, in particular of the order of 48 V, without, however, exceeding the threshold requiring the use of a galvanic isolation. In each module, a first 7f of the unitary elements is provided with a negative pole connected to a negative terminal 7n of connection of the module while a last 71 is provided with a positive pole connected to a terminal 7p, so-called positive, of the module. The negative terminals 7n of the modules are connected together. The device further comprises current regulation means 9 for controlling the level of current exchanged between the modules and the load, independently for each module.

Said regulation means 9 may be provided able to solicit said modules differently to feed the load. Thus, when the motor is traction mode, if one of the modules is more or less loaded, it will be more or less used to power the engine.

Said regulation means 9 may also be provided able to allow recharging modules differently from the load. Thus, when the engine is in generator mode, or will be able to recharge in priority the most unloaded modules. Said regulation means 9 may also be provided capable of allowing a recharge of one or more of said modules from one or more of said other modules. Thus, we can balance the load level of the modules when some are less loaded than others. The current regulation means comprise converters 10, each module 8 being connected to one of said converters, provided capable of converting the voltage delivered by the module associated with the load, in particular an increase in the voltage level. In particular, these converters are of the type enabling energy storage and restitution, in a controlled manner, for example by combining an inductive element 11, a capacitive element 12, at least one controlled switch 13 , 14 and / or at least one diode 21, 22. Said converters 10 are, for example, provided reversible so as to allow a flow of current from the modules 8 to the load 1, especially in case of operation of the engine in operation. traction, and vice versa from the load 1 to the modules 8, in particular in the case of operation of the engine in generator mode, or between the modules 8. Said converters 10 are, for example, identical from one module 8 to the other. According to the illustrated example, for each module 8 and its associated converter 10, the positive terminal 7p of the module is mounted at an input terminal 15 of the converter while the other terminal 7n of the module is connected to a first 4 of the terminals of the charge. In the converter, the input terminal 15 is connected to the inductive element 11, itself connected, on the one hand, to a first terminal 16 of a first 13 of the controlled switches and, on the other hand, to a first terminal 17 of a second 14 of the controlled switches. The first controlled switch 13 has another terminal 18, connected to the negative terminal 7n of the module. The second controlled switch 14 is connected in series with the module 8 and the inductive element 11, seen from the load. The capacitive element 12 is connected in parallel with the load and the other connection terminal 19 of the second switch 14 is connected, on the one hand, to a first terminal of said capacitive element 12 and, on the other hand, to the second terminal 5 of the load. At the other of its terminals, the capacitive element 12 is connected to the first terminal 4 of the load. A first diode 21 is provided in parallel with the first controlled switch 13. It is provided for when the voltage at the terminal 16 of the inductive element 11 opposite its terminal connected to the input terminal 15 of the converter is greater than the voltage at the negative terminal 7n of the module. A second diode 22 is provided in parallel with the second controlled switch 14. It is intended to pass when the voltage at the terminal 16 of the inductive element 11 opposite its terminal connected to the input terminal 15 of the converter is greater than the voltage at the second terminal 5 of the load. Said switches 13, 14 are constituted, for example, by IGBT or MOS transistors. In the latter case, the diodes 21, 22 are defined by the internal diodes of the transistors. The control of the open or closed states of the first switch 13 ensures the operation in step-up converter mode, between the module 8 and the load 1, as a function of the value of the duty cycle used, that is to say as a function of the time when the first switch 13 conducts the current, the second switch 14 being open. Control of the open or closed states of the second switch 14 ensures reversible operation, the first switch 13 being open.

It will of course be possible to use other types of voltage converters, in particular other converters of the type allowing recovery and restitution of energy, in a controlled and / or reversible manner. However, as illustrated, the same capacitive element can be shared between the different converters 10. Said capacitive element 12 is placed, for example, on a branch 23, provided between the terminals 4, 5 of the load and common to all converters 10. Such an embodiment has an advantage in terms of reducing the number of components. The device according to the invention may include indicators of the state of health, the load and / or the nature of each of the modules. A control unit may also be provided to use the indications provided to control the open or closed state of the controlled switches 13, 14 and provide the various modes of operation described above. In this respect, the invention also relates to a method for managing the supply of electric current to a load, in particular an electric motor vehicle engine with hybrid or electric motorization, in which a device as described above is provided. According to the method according to the invention, a current regulation is carried out making it possible to control the level of current exchanged between the modules and the load, independently for each module. It will also be possible to monitor an operating state of the modules 8, defined by the state of charge and / or the state of health of the modules 8. It will thus be possible to solicit said modules 8 in a different way to supply the load 1, according to the operating state of each of the modules 8, in particular to ensure a constant voltage and / or corresponding to the instantaneous need of the load.

It will still be possible to recharge the modules 8 differently from the load 1, depending on the operating state of each of the modules 8 and / or to recharge one or more of said modules 8 from one or several other of said modules 8, depending on the operating state of each of the modules 8. According to one embodiment, in the event of failure of one of the modules 8, the current regulation carried out is adjusted to the level of the other modules 8 to ensure the supply of a voltage to the load taking into account the absence or malfunction of the faulty module, previously detected. It will also be possible to identify the nature of each of said modules 8 and to adapt the current regulation performed for each module 8 to the nature of said module, whether to load it or to discharge it. Such an identification operation is performed, in particular, when replacing all or part of the modules.

Claims (15)

REVENDICATIONS1. Device for supplying electric current to a load (1), in particular an electric motor vehicle engine with a hybrid or electric motor, said device comprising a plurality of direct current sources (7), divided into modules (8) in which said current sources (7) are connected in series, said modules (8) being connected in parallel with the load. 2. Device according to claim 1 wherein the current sources (7) consist of identical unit elements. 3. Device according to claim 2 wherein each module (8) has the same number of unit elements (7). 4. Device according to any one of the preceding claims further comprising current control means (9) for controlling the level of current exchanged between the modules (8) and the load (1), independently for each module (8). 20 5. Device according to claim 4 wherein said regulating means (9) are provided capable of biasing said modules (8) differently to feed the load (1), to allow charging of the modules (8) in a different way since charging (1) and / or allowing recharge of one or more of said modules (8) from one or more of said other modules (8). 6. Device according to any one of claims 4 or 5 wherein the regulating means (9) comprise converters (10), each module (8) being connected to one of said converters (10), provided able to perform a voltage conversion between the associated module (8) and the load (1). 7. Device according to claim 6 wherein the converters (10) 5 are provided capable of raising the level of the voltage delivered by the modules (8). 8. Device according to any one of claims 6 or 7 wherein the converters (10) are provided reversible. 9. Device according to any one of claims 6 to 8 wherein the converters (10) comprise a capacitive element (12) connected in parallel with the load (1). 15 10. Device according to claim 9 wherein the same capacitive element (12) is shared between several of said converters (10). 11. A method for managing the electric power supply of a load (1), in particular a hybrid or electric motor vehicle electric motor machine, in which a plurality of direct current sources (7), distributed in modules (8) in which said current sources (7) are connected in series, said modules (8) being connected in parallel with the load (1), and current regulation is carried out to control the current level exchanged between the modules (8) and the load (1), independently for each module. 12. The method of claim 11 wherein one monitors a state of operation of the modules (8), defined by the state of charge and / or the state of health of the modules (8). 10 13. The method of claim 12 wherein: - said modules (8) are biased differently to feed the load (1), depending on the operating state of each of the modules (8), and / or - performs a recharging of the modules (8) differently from the load (1), depending on the operating state of each of the modules (8), and / or - one recharges one or more of said modules (8) from one or more of said modules (8), depending on the operating state of each of the modules (8). 14. A method according to any one of claims 11 to 13 in which the absence or malfunction of one of said modules (8) is detected, said module being faulty, said faulty module is isolated, and the current regulation is adjusted. level of the other modules (8) to ensure the supply of a voltage to the load taking into account the absence or malfunction of the faulty module. 15. A method according to any one of claims 11 to 14 in which the nature of each of said modules (8) is identified and the current regulation performed for each module (8) is adapted to the nature of said module.